Cutting blade mounting mechanism

ABSTRACT

A cutting blade mounting mechanism for mounting a cutting blade to a tip portion of a spindle includes: a blade mount mounted to the tip portion of the spindle; and an air supply unit supplying air to the blade mount. The blade mount includes: a columnar boss section inserted into a through-hole provided in an annular base of the cutting blade; a flange section projecting in a radial direction from a side of a base end of the boss section and having a support surface supporting the cutting blade; and an ejector type blade suction section having a first air passage connecting a supply port supplied with air from the air supply unit and a discharge port discharging air, and a second air passage connecting a suction port opening to a side of the support surface of the flange section and the first air passage.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a cutting blade mounting mechanism formounting a cutting blade to a spindle.

Description of the Related Art

A cutting apparatus having an annular cutting blade mounted to a spindleserving as a rotary shaft has been used for processing a plate-shapedworkpiece represented by a semiconductor wafer or a packaged substrate(see, for example, Japanese Utility Model Laid-Open No. Hei 5-54821).The cutting blade is mounted to a tip portion of the spindle throughmounting means such as blade mounts for clamping both sides of thecutting blade, and is replaced when worn to a certain degree.

Replacement of the cutting blade is generally carried out manually by anoperator. For the replacing operation, various tools are used so as notto damage various mechanisms in the cutting apparatus as well as themounting means, the cutting blade, and the like. Therefore, for thereplacement of the cutting blade, a certain length of operating time hasbeen required in addition to a skilled operator.

In contrast, a mounting mechanism in which a negative pressure isapplied to a cutting blade from mounting means fixed to a spindle tosuck and fix the cutting blade has been proposed (see, for example,Japanese Patent Laid-open No. 2002-154054). By use of this mountingmechanism, the cutting blade can be easily replaced in a shorter time,as compared to the case where the conventional mounting means forclamping both sides of the cutting blade is used.

SUMMARY OF THE INVENTION

Meanwhile, in the conventional cutting apparatuses, for example, an airsupply source for supplying air to a spindle or the like has been used,but a negative pressure generation source (suction source) such as avacuum pump has not been used. Accordingly, in the case of adopting theaforementioned mounting mechanism in which the cutting blade is suckedand fixed by a negative pressure, it is necessary to newly prepare anegative pressure generation source.

Therefore, it is an object of the present invention to provide a cuttingblade mounting mechanism without need to separately prepare a negativepressure generation source.

In accordance with an aspect of the present invention, there is provideda cutting blade mounting mechanism for mounting a cutting blade to a tipportion of a spindle of a cutting apparatus, the cutting apparatusincluding a chuck table holding a workpiece, and a cutting unit cuttingthe workpiece held by the chuck table by the cutting blade mounted tothe tip portion of the spindle rotatably supported by a spindle housing,the cutting blade having a cutting edge at an outer periphery of anannular base. The cutting blade mounting mechanism includes: a blademount mounted to the tip portion of the spindle; and an air supply unitsupplying air to the blade mount. The blade mount includes: a columnarboss section inserted into a through-hole provided in the annular baseof the cutting blade; a flange section projecting in a radial directionfrom a side of a base end of the boss section and having a supportsurface supporting the cutting blade; and an ejector type blade suctionsection having a first air passage connecting a supply port suppliedwith air from the air supply unit and a discharge port discharging theair, and a second air passage connecting a suction port opening to aside of the support surface of the flange section and the first airpassage, and the ejector type blade suction section sucking the cuttingblade by a negative pressure applied from the suction port.

In another aspect of the present invention, the air supply unit may be arotary joint fixed to the spindle housing and supplying air to the blademount rotated together with the spindle.

Also, in still another aspect of the present invention, an air bearingsection rotatably supporting the spindle by air and discharging the airthrough a gap between the spindle housing and the spindle toward a sideof the tip portion of the spindle may be provided inside the spindlehousing, and the supply port of the blade mount may be supplied with theair discharged through the gap.

The cutting blade mounting mechanism according to one aspect of thepresent invention includes: the air supply unit supplying air; and theblade mount including the ejector type blade suction section generatinga negative pressure by utilizing the air supplied from the air supplyunit. Therefore, since the cutting blade can be sucked and fixed by thenegative pressure generated from the blade suction section, it isunnecessary to separately prepare a negative pressure generation source.

The above and other objects, features and advantages of the presentinvention and the manner of realizing them will become more apparent,and the invention itself will best be understood from a study of thefollowing description and appended claims with reference to the attacheddrawings illustrating preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically illustrating a configurationexample of a cutting apparatus;

FIG. 2 is an exploded perspective view schematically illustrating aconfiguration example of a cutting unit;

FIG. 3 is a sectional view schematically illustrating a state before acutting blade is mounted to the cutting unit;

FIG. 4 is a sectional view schematically illustrating a state after thecutting blade is mounted to the cutting unit;

FIG. 5 is a sectional view schematically illustrating a configurationexample of a spindle and a spindle housing included in the cutting unit;

FIG. 6 is an exploded perspective view schematically illustrating aconfiguration example of a cutting unit according to a modification;

FIG. 7 is a sectional view schematically illustrating a state before acutting blade is mounted to the cutting unit according to themodification; and

FIG. 8 is a sectional view schematically illustrating a state after thecutting blade is mounted to the cutting unit according to themodification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment according to an aspect of the present invention will bedescribed with reference to the attached drawings. FIG. 1 is aperspective view schematically illustrating a configuration example of acutting apparatus into which a cutting blade mounting mechanism(hereinafter referred to as a mounting mechanism) according to thepresent embodiment is incorporated. As illustrated in FIG. 1, a cuttingapparatus 2 includes a base 4 supporting each of components.

The base 4 is formed with an opening 4 a in a front corner portion, anda cassette support base 6 lifted upward and downward by a lift mechanism(not illustrated) is provided in the opening 4 a. A cassette 8 foraccommodating a plurality of workpieces 11 is mounted on an upper faceof the cassette support base 6. Note that, in FIG. 1, only an outline ofthe cassette 8 is illustrated, for convenience of explanation.

The workpiece 11 is, for example, a circular disk-shaped wafer composedof a semiconductor material such as silicon. A front surface side of theworkpiece 11 is partitioned into a plurality of regions by a pluralityof intersecting division lines (streets), and a device 13 such as an IC(Integrated Circuit) is formed in each of the regions.

An adhesive tape (dicing tape) 15 having a diameter larger than adiameter of the workpiece 11 is adhered to a back surface side of theworkpiece 11. A peripheral portion of the adhesive tape 15 is fixed toan annular frame 17. The workpiece 11 is accommodated in the cassette 8in a state of being supported on the frame 17 through the adhesive tape15.

Note that, while the workpiece 11 is the circular disk-shaped wafercomposed of a semiconductor material such as silicon in the presentembodiment, there is no limitation to a material, a shape, a structure,a size, and the like of the workpiece 11. For example, a substratecomposed of such a material as other semiconductor, a ceramic, a resin,a metal, or the like may be cut as a workpiece. Also, there is nolimitation to a kind, a numerical quantity, a shape, a structure, asize, a layout, and the like of the device 13. The workpiece may not beformed with any device.

As illustrated in FIG. 1, on a side of the cassette support base 6, anopening 4 b which is elongate in an X-axis direction (a front-reardirection or a processing feeding direction) is formed. A ball screwtype X-axis moving mechanism 10 and a dustproof and droplet-proof cover12 covering an upper portion of the X-axis moving mechanism 10 aredisposed in the opening 4 b. The X-axis moving mechanism 10 includes anX-axis moving table 10 a, and moves the X-axis moving table 10 a in theX-axis direction.

A chuck table 14 for sucking and holding the workpiece 11 is disposed onan upper side of the X-axis moving table 10 a. The chuck table 14 isconnected to a rotational drive source (not illustrated) such as amotor, and is rotated about a rotational axis substantially parallel toa Z-axis direction (vertical direction). Also, the chuck table 14 ismoved in the X-axis direction (feeding for processing) by theabove-mentioned X-axis moving mechanism 10.

An upper face of the chuck table 14 is a holding surface 14 a forsucking and holding the workpiece 11. The holding surface 14 a is formedto be substantially parallel to the X-axis direction and a Y-axisdirection (a left-right direction or an indexing feeding direction), andis connected to an ejector (not illustrated) through a suction passage(not illustrated) and the like provided inside the chuck table 14. Inaddition, four clamps 16 for fixing the annular frame 17 supporting theworkpiece 11, from four directions, are provided in a periphery of thechuck table 14.

A carrying unit (not illustrated) for carrying the above-mentionedworkpiece 11 to the chuck table 14 and the like is disposed in a regionadjacent to the opening 4 b. The workpiece 11 carried by the carryingunit is mounted on the holding surface 14 a of the chuck table 14, forexample, in such a way that the front surface side is exposed upward.

A gate-type support structure 24 for supporting two sets of cuttingunits 22 is disposed on an upper face of the base 4 in such a manner asto straddle the opening 4 b. Two sets of cutting unit moving mechanisms26 moving each of the cutting units 22 in the Y-axis direction and theZ-axis direction are provided at an upper portion of a front face of thesupport structure 24.

The cutting unit moving mechanisms 26 shares a pair of Y-axis guiderails 28 disposed on the front face of the support structure 24 andparallel to the Y-axis direction. A Y-axis moving plate 30 constitutingeach of the cutting unit moving mechanisms 26 is slidably attached tothe Y-axis guide rails 28. A nut section (not illustrated) is providedon a back surface side (rear face side) of each of the Y-axis movingplates 30, and Y-axis ball screws 32 parallel to the Y-axis guide rails28 are screwed into the nut sections. A Y-axis pulse motor 34 isconnected to one end portion of each of the Y-axis ball screws 32. Whenthe Y-axis ball screw 32 is rotated by the Y-axis pulse motor 34, theY-axis moving plate 30 is moved in the Y-axis direction along the Y-axisguide rails 28.

A pair of Z-axis guide rails 36 parallel to the Z-axis direction isprovided on a front surface (front face) of each of the Y-axis movingplates 30. A Z-axis moving plate 38 is slidably mounted to the pair ofZ-axis guide rails 36. A nut section (not illustrated) is provided on aback surface side (rear face side) of each of the Z-axis moving plates38, and a Z-axis ball screw 40 parallel to the Z-axis guide rails 36 isscrewed into the nut section. A Z-axis pulse motor 42 is connected toone end portion of each of the Z-axis ball screws 40. When the Z-axisball screw 40 is rotated by the Z-axis pulse motor 42, the Z-axis movingplate 38 is moved in the Z-axis direction along the pair of Z-axis guiderails 36.

The cutting unit 22 is provided at a lower portion each of the Z-axismoving plates 38. The cutting unit 22 includes a spindle 44 (see FIG. 2etc.) having an axis substantially parallel to the Y-axis direction. Thespindle 44 is accommodated in an inner space of a spindle housing 46(see FIG. 2 etc.) configured in a cylindrical shape. One end portion(tip portion) 44 b (see FIG. 2 etc.) of the spindle 44 is exposedoutside the spindle housing 46, and a circular annular cutting blade 48is mounted to the one end portion 44 b.

An air supply source 50 for supplying air, and a cutting fluid supplysource 52 for supplying a cutting fluid represented by water areconnected to the cutting unit 22. Note that the air supply source 50 isconnected also to the ejector (not illustrated) for generating anegative pressure at the chuck table 14. The details of the cutting unit22 will be described later.

An imaging unit (camera) 54 for imaging the workpiece 11 and the like isprovided at a position adjacent to each of the cutting units 22. Whenthe Y-axis moving plate 30 is moved in the Y-axis direction by each ofthe cutting unit moving mechanisms 26, the cutting unit 22 and theimaging unit 54 are moved in the Y-axis direction (indexing feeding). Inaddition, when the Z-axis moving plate 38 is moved in the Z-axisdirection by each of the cutting unit moving mechanisms 26, the cuttingunit 22 and the imaging unit 54 are moved in the Z-axis direction.

An auto-blade changer 56 capable of automatically replacing the cuttingblade 48 is disposed on a rear side of the support structure 24. Theauto-blade changer 56 includes a first blade mounting/detaching unit 58and a second blade mounting/detaching unit 60 for mounting the cuttingblade 48 to the cutting unit 22 or detaching the cutting blade 48 fromthe cutting unit 22.

In addition, the auto-blade changer 56 is supported by an auto-bladechanger moving mechanism (not illustrated), and is moved between aretracted position on a rear side and a mounting/detaching position on afront side. A blade rack 62 on which the cutting blade 48 mounted to ordetached from the cutting unit 22 by the auto blade changer 56 is hookedis disposed in a vicinity of the retracted position.

An opening 4 c is formed at a position opposite to the opening 4 a withrespect to the opening 4 b. A cleaning unit 64 for cleaning theworkpiece 11 etc. after being cut is disposed in the opening 4 c. Inaddition, a control unit (not illustrated) is connected to componentssuch as the X-axis moving mechanism 10, the chuck table 14, the cuttingunits 22, the cutting unit moving mechanisms 26, the imaging units 54,the auto-blade changer 56, the auto-blade changer moving mechanism, andthe cleaning unit 64. Each of the components is controlled by thecontrol unit.

FIG. 2 is an exploded perspective view schematically illustrating aconfiguration example of the cutting unit 22. FIG. 3 is a sectional viewschematically illustrating a state before the cutting blade 48 ismounted to the cutting unit 22, and FIG. 4 is a sectional viewschematically illustrating a state after the cutting blade 48 is mountedto the cutting unit 22.

In addition, FIG. 5 is a sectional view schematically illustrating aconfiguration example of the spindle 44 and the spindle housing 46included in the cutting unit 22. As illustrated in FIG. 5, inside thespindle housing 46 (inside a wall material thereof), air supply passages46 a substantially parallel to an axis of the spindle 44 are formed.

The air supply passages 46 a are connected to the outside air supplysource 50 through an air supply port 46 b. Also, the air supply passages46 a are connected to a radial air bearing section (air bearing section)66 through first supply passages 46 c, and are connected to a thrust airbearing section (air bearing section) 68 through second air supplypassages 46 d.

By supplying high-pressure air from the air supply source 50 to theradial air bearing section 66 and the thrust air bearing section 68, thespindle 44 is kept in a floated state in the inner space of the spindlehousing 46. For example, the radial air bearing section 66 blows air tothe spindle 44 in a direction perpendicular to the axis, thereby keepingthe position of the spindle 44 constant in the direction perpendicularto the axis.

In contrast, the thrust air bearing section 68 blows air to a circulardisk-shaped thrust plate 44 a provided on the spindle 44 in a directionparallel to the axis of the spindle 44, thereby keeping the position ofthe spindle 44 constant in the direction parallel to the axis. Theradial air bearing section 66 and the thrust air bearing section 68stably support the spindle 44 rotated at a high speed.

The spindle housing 46 is provided with an opening 46 e on one end (tip)side thereof. The spindle 44 is inserted in the opening 46 e in such amanner that the one end portion (tip portion) 44 b formed in a truncatedconical shape is exposed outside the spindle housing 46. In other words,the one end portion 44 b of the spindle 44 protrudes outside the opening46 e of the spindle housing 46.

A motor 70 applying a force for rotating the spindle 44 is connected tothe other end side of the spindle 44. The motor 70 includes a stator 72fixed inside the spindle housing 46, and a rotor 74 integral with thespindle 44, and rotates the spindle 44 by a magnetic force appliedbetween the stator 72 and the rotor 74. Note that, while the spindle 44and the rotor 74 are formed integral with each other in the presentembodiment, a spindle and a rotor formed separately may be connectedtogether to be used.

Part of the air supplied to the radial air bearing section 66 and thethrust air bearing section 68 is discharged (jetted out) outside thespindle housing 46 through an air seal section (air seal) 76corresponding to a gap between the one end portion 44 b of the spindle44 and the opening 46 e of the spindle housing 46.

This air flow seals (air-seals) the gap between the one end portion 44 bof the spindle 44 and the opening 46 e of the spindle housing 46. Inother words, foreign matter such as cutting dust (cutting chips) wouldnot enter the inner space of the spindle 44 through the gap between theone end portion 44 b of the spindle 44 and the opening 46 e of thespindle housing 46.

As illustrated in FIGS. 2 and 3, a rotary joint (air supply unit) 78constituting the mounting mechanism according to the present embodimentis attached to one end face (tip face) 46 f of the spindle housing 46.The rotary joint 78 includes a plate-shaped base section 80, and acylindrical accommodation section 82 projecting to a front surface 80 aside (a side opposite to the spindle housing 46) of the base section 80.

The base section 80 is provided in a central portion thereof with athrough-hole 80 b through which to pass the one end portion 44 b of thespindle 44. In addition, one end face 46 f of the spindle housing 46 isprovided with a plurality of tapped holes 46 g, and the base section 80is provided with a plurality of through-holes 80 c corresponding to thetapped holes 46 g. Therefore, by tightening screws (not illustrated) tothe tapped holes 46 g through the through-holes 80 c, the rotary joint78 can be fixed to the spindle housing 46.

A tubular connection section 84 having an air passage 84 a therein isdisposed on a peripheral side of the accommodation section 82. The airsupply source 50 is connected to one end of the connection section 84(air passage 84 a). In addition, the other end side of the connectionsection 84 (air passage 84 a) is connected to an inner space of theaccommodation section 82 through a through-hole 82 a provided in theaccommodation section 82. This enables air of the air supply source 50to be supplied into the inner space of the accommodation section 82.

In a state in which the rotary joint 78 is fixed to the spindle housing46, a blade mount 86 constituting the mounting mechanism according tothe present embodiment is mounted to the one end portion 44 b of thespindle 44. The blade mount 86 includes a cylindrical boss section(insertion section) 88, and a circular disk-shaped flange section 90projecting radially outward from a base end side of the boss section 88.

A recess 90 a into which the one end portion 44 b of the spindle 44 isinserted is provided in a central portion on a back surface side (thespindle housing 46 side) of the flange section 90. In addition, the bosssection 88 is provided in a central portion thereof with a through-hole88 a reaching the recess 90 a. Further, an end face (tip face) of theone end portion 44 b of the spindle 44 is formed with a tapped hole 44c.

Therefore, the one end portion 44 b of the spindle 44 is inserted intothe recess 90 a, and a screw 92 is tightened to the tapped hole 44 c ofthe spindle 44 through the through-hole 88 a of the blade mount 86, sothat the blade mount 86 can be fixed to the spindle 44. As a result, theblade mount 86 can be rotated together with the spindle 44.

Note that a diameter of the inner space of the accommodation section 82is slightly larger than a diameter of a back-side portion 90 b of theflange section 90, and when the blade mount 86 is fixed to the spindle44, the back-side portion 90 b of the flange section 90 is accommodatedin the inner space of the accommodation section 82. A peripheral side ofa front surface (a surface opposite to the spindle housing 46) of theflange section 90 is a support surface 90 c supporting the cutting blade48. This support surface 90 c is formed in a circular annular shape asviewed from the axial direction of the spindle 44.

The cutting blade 48 is a so-called hub blade in which a circularannular cutting edge 96 for cutting the workpiece 11 is provided at anouter peripheral portion of a circular annular base 94. The cutting edge96 is formed, for example, by dispersing abrasive grains of diamond, CBN(Cubic Boron Nitride), or the like in a bonding material (binder) suchas a metal or a resin.

In a central portion of the base 94, a through-hole 94 a into which theboss section 88 is to be inserted (passed) is formed. At the time ofmounting the cutting blade 48 to the blade mount 86, the boss section 88is inserted into the through-hole 94 a, and the back surface side of thebase 94 is brought into contact with the support surface 90 c of theflange section 90, as illustrated in FIG. 4.

As illustrated in FIGS. 3 and 4, inside the blade mount 86 (inside awall material thereof), an ejector type blade suction section 98 isprovided. The blade suction section 98 includes a supply port 100opening in a peripheral face of the back-side portion 90 b of the flangesection 90. This supply port 100 is formed in an annular shape along acircumferential direction of the peripheral face of the back-sideportion 90 b.

In addition, the supply port 100 is formed at a position correspondingto the through-hole 82 a provided in the accommodation section 82, in astate in which the back-side portion 90 b of the flange section 90 isaccommodated in the inner space of the accommodation section 82.Therefore, air from the air supply source 50 is supplied through thethrough-hole 82 a to the supply port 100. Note that, since the supplyport 100 is formed in an annular shape as described above, the supply ofair to the supply port 100 is not stagnated even when the blade mount 86is rotated together with the spindle 44.

The supply port 100 is connected to a discharge port 104 opening to afront surface side of the boss section 88, through first air passages102 formed inside the blade mount 86. The air supplied through thethrough-hole 82 a of the rotary joint 78 to the supply port 100 isdischarged outside the blade mount 86 through the first air passages 102and from the discharge port 104.

A suction port 108 opening to a support surface 90 c side of the flangesection 90 is connected to a midstream portion of each of the first airpassages 102 through each of second air passages 106. In connectionregions A between the first air passages 102 and the second air passages106, an inner diameter of the first air passage 102 is smaller than inother regions. Therefore, a flow speed of air flowing through the firstair passage 102 is enhanced in the connection region A, and theconnection region A is reduced in pressure by the Venturi effect.

This causes air in the second air passage 106 to flow into the first airpassage 102, and a negative pressure from the suction port 108 isapplied to a back surface side of the cutting blade 48. The cuttingblade 48 is sucked and fixed to the blade mount 86 by this negativepressure. Note that an inner diameter of the second air passage 106 inthe connection region A is desirably smaller than the inner diameter ofthe first air passage 102. This makes it difficult for the air flowingthrough the first air passage 102 to flow into the second air passage106.

As has been described above, the cutting blade mounting mechanismaccording to the present embodiment includes the rotary joint (airsupply unit) 78 for supplying air, and the blade mount 86 including theejector type blade suction section 98 generating a negative pressure byutilizing the air supplied from the rotary joint 78. Therefore, sincethe cutting blade 48 can be sucked and fixed by the negative pressuregenerated from the blade suction section 98, it is unnecessary toseparately prepare a negative pressure generation source.

Note that the present invention is not limited to the description of theabove embodiment and the like, but may be carried out with variousmodifications. For example, although the two first air passages 102, thetwo discharge ports 104, the two second air passages 106, and the twosuction ports 108 are provided in the above embodiment, the numericalquantity, the layout, and the like of each of components of the bladesuction section 98 are not particularly limited. For example, thenumbers of the second air passages 106 and the suction ports 108 may beincreased.

In addition, although the blade mount 86 (or the cutting blade 48) is soconfigured that the base 94 (back surface side) of the cutting blade 48comes into contact with the support surface 90 c of the flange section90 in the above embodiment, the blade mount 86 (or the cutting blade 48)may be configured in such a manner that the cutting edge 96 of thecutting blade 48 comes into contact with the support surface 90 c of theflange section 90.

Also, although the cutting apparatus 2 in the above embodiment includesthe auto-blade changer 56 automatically capable of replacing the cuttingblade 48, the auto-blade changer 56 may be omitted. Further, although acase where the adhesive tape 15 is adhered to a back surface side of theworkpiece 11 and the front surface side of the workpiece 11 is exposedhas been described in the above embodiment, the adhesive tape 15 may beadhered to the front surface side of the workpiece 11 and the backsurface side of the workpiece 11 may be exposed.

In addition, although the cutting apparatus 2 in the above embodimentincludes the rotary joint 78 for supplying air to the blade mount 86,other air supply unit may also be provided. FIG. 6 is an explodedperspective view schematically illustrating a configuration example of acutting unit 22 a according to a modification. FIG. 7 is a sectionalview schematically illustrating a state before the cutting blade 48 ismounted to the cutting unit 22 a according to the modification, and FIG.8 is a sectional view schematically illustrating a state after thecutting blade 48 is mounted to the cutting unit 22 a according to themodification.

As illustrated in FIGS. 6, 7 and 8, the cutting unit 22 a according tothe modification includes a plate-shaped adjusting plate (air supplyunit) 110 for adjusting the flow of air discharged through the gapbetween the one end portion 44 b of the spindle 44 and the opening 46 eof the spindle housing 46. Note that most of the components of thecutting unit 22 a according to the modification are the same as those ofthe cutting unit 22 according to the above embodiment. Therefore, thecommon components are denoted by the same reference symbols, anddetailed description of them will be omitted.

In a central portion of the adjusting plate 110, a through-hole 110 athrough which the air discharged through the gap between the one endportion 44 b of the spindle 44 and the opening 46 e of the spindlehousing 46, together with the one end portion 44 b of the spindle 44,passes is provided. In addition, the adjusting plate 110 is providedwith a plurality of through-holes 110 b corresponding to the pluralityof tapped holes 46 g of the spindle housing 46. Therefore, screws (notillustrated) are tightened to the tapped holes 46 g through thethrough-holes 110 b, so that the adjusting plate 110 can be fixed to thespindle housing 46.

A blade suction section 98 a according to the modification includes anannular supply port 112 opening to the back surface side of the flangesection 90. This supply port 112 is formed, for example, at a positionand in a size corresponding to the through-hole 110 a of the adjustingplate 110. The air discharged through the gap between the one endportion 44 b of the spindle 44 and the opening 46 e of the spindlehousing 46 is supplied to the supply port 112 through the through-hole110 a of the adjusting plate 110.

The supply port 112 is connected to a discharge port 116 opening to thefront surface side of the boss section 88, through first air passages114 formed inside the blade mount 86. The air supplied to the supplyport 112 through the through-hole 110 a of the adjusting plate 110 isdischarged outside the blade mount 86 through the first air passages 114from the discharge port 116.

Each of suction ports 120 opening to the support surface 90 c side ofthe flange section 90 is connected to a midstream portion of each of thefirst air passages 114 through second air passages 118. In theconnection region A between the first air passage 114 and the second airpassage 118, an inner diameter of the first air passage 114 is smallerthan in other regions. Therefore, the flow speed of air flowing throughthe first air passage 114 is enhanced in the connection region A, andthe connection region A is reduced in pressure by the Venturi effect.

This causes the air in the second air passage 118 to flow into the firstair passage 114, and a negative pressure from the suction port 120 isapplied to the back surface side of the cutting blade 48. The cuttingblade 48 is sucked and fixed to the blade mount 86 by this negativepressure. Note that an inner diameter of the second air passage 118 inthe connection region A is desirably smaller than the inner diameter ofthe first air passages 114. This makes it difficult for the air flowingthrough the first air passage 114 to flow into the second air passage118.

In addition, the structure, the method, and the like according to thepresent embodiment and the present modification can be carried out withappropriate modifications without departing from the scope of theobjects of the present invention.

The present invention is not limited to the details of the abovedescribed preferred embodiments. The scope of the invention is definedby the appended claims and all changes and modifications as fall withinthe equivalence of the scope of the claims are therefore to be embracedby the invention.

What is claimed is:
 1. A cutting blade mounting mechanism for mounting a cutting blade to a tip portion of a spindle of a cutting apparatus, the cutting apparatus including a chuck table holding a workpiece, and a cutting unit cutting the workpiece held by the chuck table by the cutting blade mounted to the tip portion of the spindle rotatably supported by a spindle housing, the cutting blade having a cutting edge at an outer periphery of an annular base, the cutting blade mounting mechanism comprising: a blade mount mounted to the tip portion of the spindle; and an air supply unit supplying air to the blade mount, wherein the blade mount includes: a columnar boss section inserted into a through-hole provided in the annular base of the cutting blade; a flange section projecting in a radial direction from a side of a base end of the boss section and having a support surface supporting the cutting blade; and an ejector blade suction section having a first air passage connecting a supply port supplied with air from the air supply unit and a discharge port discharging the air, and a second air passage connecting a suction port opening to a side of the support surface of the flange section and the first air passage, and the ejector blade suction section sucking the cutting blade by a negative pressure applied from the suction port.
 2. The cutting blade mounting mechanism according to claim 1, wherein the air supply unit is a rotary joint fixed to the spindle housing and supplying air to the blade mount rotated together with the spindle.
 3. The cutting blade mounting mechanism according to claim 1, wherein an air bearing section rotatably supporting the spindle by air and discharging the air through a gap between the spindle housing and the spindle toward a side of the tip portion of the spindle is provided inside the spindle housing, and the supply port of the blade mount is supplied with the air discharged through the gap. 